frustrates is a form of:

Telegraphy



noun
1.
(the operation of telegraph apparatus, the process of communication by telegraph) ទូរលេខសាស្ដ្រ
2.
(បច្ចេកទេស) ទូរលេខសាស្រ្ត
ENGLISH MEANING
noun
1.
The science or art of constructing, or of communicating by means of, telegraphs; as, submarine telegraphy.